Modified tubular

ABSTRACT

A positioning member for a tubular is formed using a prefabricated fibre-reinforced resin shell positioned upon a surface of the tubular and bonded to provide a protrusion upon the surface of the tubular. In a disclosed method a fibre-reinforced resin shell is secured to an external surface of a tubular thereby enclosing a cavity between the shell and the surface of the tubular; a bonding agent is introduced through inlet ports in a surface of the fibre-reinforced resin shell to fill a cavity between the shell and the surface of the tubular ( 10 ), and the bonding agent is cured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/374,442 filed 24 Jul. 2014, which is a U.S. National Stageapplication of PCT/EP2013/057416 filed 9 Apr. 2013, which claimspriority to Great Britain patent application 1215868.9 filed 5 Sep.2012, the entire disclosures of which are incorporated herein byreference.

BACKGROUND

Oil and gas reservoirs may be exploited by tapping the resources thereinvia wellbores. Drilling of wellbores may require drilling a considerabledistance into the earth. Many oil & gas bearing formations are atsub-sea locations. The direction of drilling may vary from a verticalposition to a horizontal position. The wellbore created by drilling maybe stabilised by use of casing or lining or by other measures. Tubularbodies (hereinafter “tubulars”) may be positioned in the wellbore. Thetubular bodies may be cemented into position. The positioning oftubulars in the wellbore may be complicated by variations in wellboredirection. Tubulars may have mechanical components mounted thereon forthe purposes of improving alignment and stable positioning of thetubulars in the wellbore. Correct positioning of the tubulars permitscementing to a satisfactory standard.

SUMMARY

A positioning member may be formed and applied to a tubular. The formingprocess may comprise prefabrication of an outer part followed byapplication and bonding of the outer part to the tubular. The formedpositioning member provides a protrusion upon the surface of thetubular.

The positioning member may comprise a shell configured to a desiredexternal shape. The external shape of the shell may be configured toform straight, curved, helical or spiral shaped positioning members. Theshell may have an external contact or bearing surface, which may begenerally planar or outwardly curved (convex), with bevelled sidesurfaces. The shell may have peripheral edges including portions adaptedto allow passage of a flowable material. The peripheral edge portionsmay be indented, recessed, notched, serrated, apertured, crenulated,slotted or otherwise include a discontinuity which may form a flow portwhen the peripheral edge is presented against a parallel surface. Thedepth of the shell is selected to provide a clearance or spaced positionfrom a surface such as the wall of a borehole.

The interior surface of the shell may be configured to provide aplurality of projections, curved ridges, a fish scale pattern or anyother relief pattern.

The shell may be structurally reinforced by provision of one or morestrengthening members. The strengthening member may be a strut, brace, arib or an equivalent thereof. Such structural reinforcement may extendbetween two opposite sides of the shell.

The shell may be formed from a composite material. The compositematerial may be a fibre-reinforced resin material (FRP/GRP/GFK typematerial). The resin material is a hardenable resin optionally includingcuring agents and curing modifiers. The resin may be self-curing, orprovided in two components which harden when brought together. The twocomponent system may be a matrix-forming (pre-polymer) component and ahardener. Suitable resins include epoxy resins, polyurethanes andpolyurea resins including blends or hybrids thereof, and other curableresin components including polyester or polyol or polyamine components.The curing of the resin may be controlled by use of amine curing agentssuch as polyetheramines. Other additives may be present.

The fibre-reinforced resin material may be surface treated beforemoulding of the shell. The fibre-reinforced resin material may have aceramic particulate applied. The fibre-reinforced material may have afriction-modifying material applied. A combination of such surfacetreatments may be used. The surface treatment may be a surface modifyingfinish to an external surface of the moulded shell.

Additional particulate materials may be present within the bulk of thefibre-reinforced resin material. The particulates may be in bead form.

The shell may have at least one inlet for passage of flowable materials,such as bonding agents. The shell may be bonded to an external surfaceof a tubular. Bonding agents may be introduced into a void between thetubular and the shell by injection through the at least one inlet.

The shell may be temporarily located upon a tubular, prior tointroducing bonding agents into the shell, using temporary fastenings soas to enclose a void between the tubular and the shell. The temporaryfastenings may be a contact adhesive or releasable fasteners which mayinclude ties, wires, straps, an adhesive tape and various combinationsthereof.

Embodiments incorporate the disclosed summary features individually orin a variety of combinations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view from below and to one side of a fibrereinforced composite shell body;

FIG. 2 is a perspective view form above and to one side of a fibrereinforced composite shell body;

FIG. 3 is a perspective view from one end of a fibre reinforcedcomposite shell body; and

FIG. 4 is a side view of a tubular modified by application of fibrereinforced composite shell bodies.

DETAILED DESCRIPTION Manufacture of Shell

In an embodiment, a permanent mould or form is designed and constructedaccording to shape requirements for the shell form to be manufactured,that is, the geometry required for the intended positioning member. Theshape requirements are derived from known dimensions of a tubular andits intended use in a wellbore. A choice can be made amongst protrusionsof straight, curved or spiral or helical configurations. A number ofdiffering moulds may be produced to enable a variety of positioningmembers to be manufactured at will.

The mould is used to form materials into a prefabricated shell which issuitable to form part of a positioning member which is to be provide ona tubular.

In an embodiment, a fibre mat is infused with a resin matrix. This isachievable by passing the fibre mat through a bath containing the resinmatrix. Infusion may also be achievable in other ways, such as applyingthe resin matrix liberally to the fibre mat by pouring or spraying or bya pressure treatment to soak, or impregnate the fibre mat with the resinmatrix.

Ceramic particulates, for example hard wearing materials such as acombination of zirconium dioxide and silicon nitride, optionally in beadform, may be applied to the resin matrix infused fibre mat.

A friction modifying material such as fluorocarbon particulatesproviding a low friction coefficient also may be applied to the resinmatrix infused mat.

The resin matrix infused fibre mat may be introduced to the mould suchthat surfaces treated with the aforesaid particulates are adjacent tothe mould surfaces. Multiple additional layers of the resin matrixinfused fibre mat, which may or may not each have been treated withparticulates, may be laid up into the mould on to the first resin matrixinfused fibre mat lining the mould until a predetermined thickness isattained.

Then the mould may be closed.

A resin filler matrix may be introduced into the mould using a lowpressure resin transfer moulding process. In an example of such aprocess, a mixed resin and catalyst or resin curing agent areintroduced, for example by injection, into a closed mould containing aresin matrix infused fibre and particulates lay up. In this way acomposite shell may be formed.

The mould may be heated in order to achieve first cure.

After sufficient curing of the resin to permit handling of the shell,the mould can be opened and the formed shell removed.

If necessary a post cure of the formed shell may be carried out. Postcure may be a heat treatment, for example conducted in an oven.

Technical Features of the Shell

Referring to FIG. 2, an embodiment of the shell 1 has an outer contactor bearing surface 2 which is generally planar with peripheral slopingor bevelled sides 3, 4 and ends 6, 8. Other embodiments may have aconvex curved bearing surface or faceted contour surface. The outerbearing surface 2 is provided with injection inlet ports 5.

Referring to FIG. 1, the shell has peripheral edges 13, 14 adapted toallow passage of a flowable material. Provision of recesses 23, 24 inportions of the peripheral edges 13, 14 provides a series of apertureswhen the peripheral edges 13, 14 are in contact with a parallel surface.

Referring to FIG. 1, an inner surface 12 of the shell 1 is configured toprovide a plurality of curved ridges 15, or fish scale pattern, toprovide a keying surface to improve adhesion or bonding with a bondingmaterial.

Optionally, the shell is formed to include structural reinforcementssuch as one or more integral strengthening struts, braces or ribs 16extending from one side 3 to an opposite side 4. One such transversestrut 16 is shown in FIG. 1.

Modification of a Tubular

In use of the shell 1 to form a positioning member 11, a selected outersurface area of a tubular 10 is prepared in order to provide a clean,dry substrate with an appropriate surface profile for receiving theshell.

A prefabricated shell 1 of appropriate dimensions is presented to theprepared area, so that edges 13 and 14 are contiguous with the surfaceof the tubular. The shell 1 is held in position temporarily by use ofreleasable fastenings such as removable straps, or adhesive tape. Acavity is thereby defined between interior surfaces of the shell 1 andthe prepared area of the tubular.

A bonding material is injected into the shell cavity through one or moreinlet ports 5 in the surface of the shell 1 until it flows through theapertures defined between the recesses 23, 24 and the surface of thetubular.

When a period sufficient for curing of the bonding material has elapsed,the straps and/or adhesive tape may be removed.

By this method the prefabricated shell becomes an integral part of thepositioning member bonded to the tubular.

The tubular is thereby modified to have a surface mounted positioningmember which facilitates appropriate positioning of the tubular in aborehole.

Additional positioning members may be formed on the tubular byrepetition of the above described methods and procedures.

Variations, modifications of the disclosed embodiments contemplated bythe person skilled in the field are within the scope of the disclosure,and with regard to scope, attention is directed to the following claimswhich form part of the present disclosure and extend to all equivalentsof the disclosed subject matter.

What is claimed is:
 1. A tubular having at least one positioning memberbonded thereto, the positioning member comprising a shell that isfabricated prior to placement on the tubular and a bonding material forbonding the shell to the tubular.
 2. The tubular claimed in claim 1,wherein the prefabricated shell is formed from a composite material andhas a surface comprising particulates conferring surface abrasionresistance properties.
 3. The tubular claimed in claim 1, wherein theprefabricated shell is formed from a composite material and has asurface comprising particulates conferring low friction coefficientproperties.
 4. The tubular claimed in claim 1, wherein the prefabricatedshell is formed from a composite material and has a surface comprisingparticulates conferring surface abrasion resistance and particulatesconferring low friction coefficient properties.
 5. The tubular claimedin claim 1, wherein the cured bonding material substantially fills theinterior of the prefabricated shell.
 6. The tubular claimed in claim 1,wherein the prefabricated shell comprises a fibre reinforced mat infusedwith a resin matrix, and the fibre reinforced mat infused with a resinmatrix has ceramic particulates on at least a surface thereof.
 7. Thetubular claimed in claim 6, wherein the fibre reinforced mat infusedwith a resin matrix has friction reducing fluorocarbon particulates onat least a surface thereof.
 8. The tubular claimed in claim 6, whereinparticulate materials are provided within the fibre reinforced matinfused with a resin matrix.
 9. The tubular claimed in claim 8, whereinthe particulate materials provided within the fibre reinforced matinfused with a resin matrix are selected from the group consisting ofparticulates conferring surface abrasion resistance and particulatesconferring low friction coefficient properties.
 10. The tubular claimedin claim 1, wherein the prefabricated shell comprises ceramic beads onat least one outer surface thereof.
 11. The tubular claimed in claim 10,wherein the ceramic beads comprise zirconium dioxide and siliconnitride.
 12. The tubular claimed in claim 1, wherein the prefabricatedshell has an external planar bearing surface and bevelled side surfaces.13. The tubular claimed in claim 1, wherein the prefabricated shell hasan external convex curved bearing surface and bevelled side surfaces.14. A method comprising forming composite materials into a shell havingan external bearing surface and bevelled side surfaces, wherein thecomposite materials comprise fibre-reinforced resins and particulatesselected from the group consisting of particulates conferring surfaceabrasion resistance and particulates conferring low friction coefficientproperties.
 15. The method claimed in claim 14, wherein the shell isformed to have edge portions adapted to allow passage of a flowablematerial.
 16. The method claimed in claim 14, wherein an interiorsurface of the shell is configured to provide a plurality ofprojections.
 17. The method claimed in claim 14, wherein an interiorsurface of the shell is configured to provide a plurality of curvedridges.
 18. The method claimed in claim 14, wherein an interior surfaceof the shell is configured to provide a relief pattern e.g. a fish scalepattern.
 19. The method claimed in claim 14, wherein an interior surfaceof the shell is configured to provide structural reinforcement.
 20. Themethod claimed in claim 19, wherein the structural reinforcementcomprises at least one strengthening member extending between twoopposite sides of the shell.
 21. The method claimed in claim 20, whereinthe at least one strengthening member is at least one member selectedfrom the group consisting of a strut, a brace and a rib.
 22. The methodclaimed in claim 14, wherein the shell is formed to have a geometryselected from the group consisting of straight, curved, helical andspiral configurations.
 23. The method claimed in claim 14, wherein theshell is formed to include at least one inlet port for passage offlowable materials.
 24. A method comprising forming a positioning memberon a tubular by applying a prefabricated composite shell to a surface ofthe tubular and introducing bonding material to a cavity formed betweenthe surface of the tubular and the prefabricated composite shell, andcuring the bonding material.
 25. The method claimed in claim 24, whereinthe prefabricated composite shell has an external surface comprisingparticulates selected from the group consisting of particulatesconferring surface abrasion resistance and particulates conferring lowfriction coefficient properties.